The invention relates to semiconductor fabrication, and particularly to fabricating transistor devices having diamond-shaped source and drain regions.
Field effect transistors (FETs) are commonly employed in electronic circuit applications. FETs may include a source region and a drain region spaced apart by a semiconductor channel region. A gate, potentially including a gate dielectric layer, a work function metal layer, and a metal electrode, may be formed above the channel region. By applying voltage to the gate, the conductivity of the channel region may increase and allow current to flow from the source region to the drain region.
Carrier mobility in the channel of a FET device can be improved by applying mechanical stresses to the channel to induce tensile and/or compressive strain in the channel. The application of such mechanical stresses to the channel can modulate device performance and thus improve the characteristics of the FET device. For example, a process-induced tensile strain in the channel of an n-type (NFET) device can create improved electron mobility, leading to higher saturation currents. For p-type FETs (pFETs), compressive stress may be applied.